Different articles made from material injection, for example plastic, and comprising a magnet or magnetic element in at least one of their faces are known today. This magnet enables the article to be arranged on ferric surfaces or to be coupled to another article. One example of these articles is the different toys or promotional figures having the magnet in their base to enable arranging them more or less firmly on a ferric surface.
Another example is that of those known as “refrigerator magnets” which also comprise a body or decorative part, provided with a flat rear part, provided with a hollow in which the magnet allowing the fixing thereof is located.
As mentioned, in most of these articles the magnet is arranged in a housing or hole of the body and fixed by means of an adhesive or glue. This conformation poses a technical problem consisting of the possibility of magnet detachment which is dangerous especially in toys due to the risk of an accident in children who may swallow the magnet.
If attempts are made to place the magnet inside the mould before injecting the material forming the body of the article, this magnet is embedded inside the body and is not removable. However the high temperature with which the material of the body is injected into the mould affects the magnetic properties of the magnet which can become demagnetised.
In certain cases the magnet can lose all its magnetic capacity due to the high temperature obtained inside the mould, and therefore the article is useless.
This demagnetisation risk does not allow assuring the product manufacturing reliability and is unacceptable both for the manufacturer and for the possible customers or users thereof.
Another problem lies in the difficulty of placing the magnet inside the injection mould before injecting the material of the body since the magnet can move from its place due to the pressure of the injected material.
European patent EP455921 “Magnet to be assembled with an injected plastic material”, describing a magnet having at least two grooves or groups of grooves inclined with respect to the base on its side faces and located on two opposite areas of the magnet, is known. This magnet is then embedded in an injected plastic material.
These magnets are applied in multiple transducers such as drives for loom or printer needles. This magnet is intended for light use, such as for activating transducers, where the magnetic field of the magnet must not have such a strong force so as to adhere an entire body of a toy article. Furthermore, in the applications described in said European patent the magnet detachment is not as risky as in a toy or promotional article, so the solution described is not applicable to the technical problem considered.